Variable temporal length 3D DCT-DWT based video coding

Almost all variable length 3D-DCT algorithms employ thresholds. Although the selection of threshold considerably affects the algorithm performance, there is no framework to choose them effectively. This paper proposes a hybrid transform for 3D-DCT based video coding. In the proposed model, 3D-DCT and discrete Haar transform are iteratively used to remove the redundancy for each cube and thus an adaptive scheme is derived to realize variable temporal length of DCT implementations. Compared to other methods in the literature, the proposed model can mathematically select the optimal DCT mode and remove the temporal correlations more effectively. Experimental results show that the proposed approach has substantial improvement over the conventional fixed-length 3D-DCT coding and other variable length 3D-DCT coding.